How to play Neon Tube Sort
Neon Tube Sort is a pour-sorting puzzle. Seven glass tubes hold five glowing neon liquids — cyan, magenta, lime, amber and violet — each appearing in exactly four segments, scrambled at random. Two tubes start empty to give you working space. Click a tube to lift its top layer, then click a second tube to pour. Liquid only flows onto a matching color or into an empty tube, and only the unbroken run of one color on top will pour. Your goal is five tubes of pure single colors, with two tubes left empty.
Controls
Click or tap any tube to select it — it rises and glows magenta. Click a destination tube to pour, or click the selected tube again to set it back down. Keyboard players can press 1 through 7 to pick tubes in order, and U at any time to undo the last pour. The undo stack is unlimited, so you can rewind the whole puzzle.
Tips & strategy
Plan before you pour: a random pour often buries the color you need next. Use one empty tube as a buffer for stray segments and keep the other for building a pure color. Focus on freeing the color with the most segments trapped at the bottom of mixed tubes — once one tube is pure, it stops being a problem and starts being storage. If you get stuck, undo a few moves rather than starting over; most dead ends are only two or three pours deep.
Scoring
Every pour counts as one move — fewer moves means a sharper solution. Each puzzle is guaranteed solvable, and your fewest-move record for a puzzle is saved in your browser. There is no timer and no penalty for undoing, so take the slow, elegant route.